There are only five students in the whole school. Abydos High School, surrounded by desert, is on the verge of closure. To fight against this, the 5 of them are busy working as a "task force." One day, Shiroko, a student, meets an adult. He was a "Sensei" dispatched by the Federal Student Council.
After meeting Sensei, the Task Force begins to see hope for preventing the closure of their school. They have even defeated the approaching Helmet Gang, and their hopes are gradually growing. However, only one of them, Serika, seems unable to accept her teacher. Then danger approaches her?!
The Task Force and Sensei try to solve the problem at hand, but the amount of debt is so huge that they sigh. Unable to come up with a solution, they go into a ramen shop and hit it off with a group of girls who call themselves "Problem Solver 68," a group of outlaws. The next day, however, "Problem Solver 68" begins to attack Abydos High School?!
The Abydos Task Force heads to the "Black Market," a famously lawless area, in pursuit of clues about the Helmet Gang that attacked them. While investigating with "Hifumi," a girl from Trinity General School that they happened to meet, they discover a possibility that the repaid money was flowing into a black market. There, Shiroko suddenly shouts, "We're gonna rob the bank!"